In seed cleaning operations, the quality of the final seed mixture is an important factor. Conventional seed cleaning systems utilize screens and air to remove foreign matter and other undesirable materials from the desired seeds. Typically, two air separation stages are provided for lifting and removing lightweight materials. The first air-lift is located at the seed hopper and draws a strong stream of air through the entire bulk of seed as it feeds into the cleaning machine. This initial air-lift removes most of the light trashy material from the seed bulk. A second air-lift is normally located adjacent the outlet of the cleaning machine where the cleaned seeds are discharged. This second air-lift removes any remaining light off-grade seeds, hollow kernels, or broken seeds which are not sifted by the screens. The terminal velocity of the seed is an important operating criterion, and proper adjustment of the air-lift is crucial for efficient separation and cleaning
Typically, at least two screens are also utilized for cleaning the seed. The first or top screen removes coarse foreign material which is larger than the seed, while allowing the seed, dirt, and other small particles to pass through onto the finer second or bottom screen. This second screen retains the clean seed on top, while allowing the foreign material which is smaller than the seed to pass through. The feed rate along the screens must be properly adjusted to obtain maximum and efficient performance.
In these conventional seed cleaning machines, the adjustments of the air-lift vacuum and the screen feed rate are accomplished manually by visual inspection and trial and error. Frequent supervision and adjustment by the operator is necessary to maintain the seed quality with minimum seed loss. Also, such manual adjustments are made at spaced timed intervals, and therefore necessarily attempt to correct problems which have already allowed foreign matter to remain in the finished seed product and/or allowed good seed to be removed with the waste by the screens and air-lift.
Therefore, a primary objective of the present invention is the provision of an improved seed cleaning system which allows for maximization of cleaning efficiency.
Another objective of the present invention is the provision of an improved seed cleaning system which is continuously monitored and adjusted for controlling the efficiency of the operation.
A further objective of the present invention is the provision of a seed cleaning system having an improved airlift spout.
Yet another objective of the present invention is the provision of a seed cleaning system having an improved screening spout.
Still another objective of the present invention is the provision of a seed cleaning system having a computer processing unit for monitoring and adjusting the seed cleaning operation, if desired.
These and other objectives will become apparent from the following description of the present invention.